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// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.functions.Monotonic;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullLiteral;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
import org.apache.doris.nereids.trees.expressions.literal.DateTimeLiteral;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.BigIntType;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.types.DateTimeV2Type;
import org.apache.doris.nereids.types.DateV2Type;
import org.apache.doris.nereids.types.DecimalV3Type;
import org.apache.doris.nereids.types.StringType;
import org.apache.doris.nereids.types.VarcharType;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * ScalarFunction 'unix_timestamp'. This class is generated by GenerateFunction.
 */
public class UnixTimestamp extends ScalarFunction
        implements ExplicitlyCastableSignature, PropagateNullable, PropagateNullLiteral, Monotonic {
    // we got changes when computeSignature
    private static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(BigIntType.INSTANCE).args(),
            FunctionSignature.ret(DecimalV3Type.WILDCARD).args(DateTimeV2Type.WILDCARD),
            FunctionSignature.ret(BigIntType.INSTANCE).args(DateV2Type.INSTANCE),
            FunctionSignature.ret(DecimalV3Type.createDecimalV3Type(18, 6)).args(VarcharType.SYSTEM_DEFAULT,
                            VarcharType.SYSTEM_DEFAULT),
            FunctionSignature.ret(DecimalV3Type.createDecimalV3Type(18, 6)).args(StringType.INSTANCE,
                    StringType.INSTANCE)
    );

    /**
     * constructor with 0 argument.
     */
    public UnixTimestamp() {
        super("unix_timestamp");
    }

    /**
     * constructor with 1 argument.
     */
    public UnixTimestamp(Expression arg) {
        super("unix_timestamp", arg);
    }

    /**
     * constructor with 2 arguments.
     */
    public UnixTimestamp(Expression arg0, Expression arg1) {
        super("unix_timestamp", arg0, arg1);
    }

    /** constructor for withChildren and reuse signature */
    private UnixTimestamp(ScalarFunctionParams functionParams) {
        super(functionParams);
    }

    @Override
    public FunctionSignature computeSignature(FunctionSignature signature) {
        signature = super.computeSignature(signature);
        if (arity() != 1) {
            return signature;
        }
        DataType argType0 = getArgumentType(0);
        if (argType0.isDateTimeV2Type()) {
            int scale = ((DateTimeV2Type) argType0).getScale();
            return signature.withReturnType(DecimalV3Type.createDecimalV3Type(12 + scale, scale));
        } else if (argType0.isStringLikeType()) {
            return signature.withReturnType(DecimalV3Type.createDecimalV3Type(18, 6));
        }
        return signature;
    }

    /**
     * withChildren.
     */
    @Override
    public UnixTimestamp withChildren(List<Expression> children) {
        Preconditions.checkArgument(children.isEmpty()
                || children.size() == 1
                || children.size() == 2);
        return new UnixTimestamp(getFunctionParams(children));
    }

    @Override
    public List<FunctionSignature> getSignatures() {
        return SIGNATURES;
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitUnixTimestamp(this, context);
    }

    @Override
    public boolean isDeterministic() {
        return !this.children.isEmpty();
    }

    @Override
    public boolean isPositive() {
        return true;
    }

    @Override
    public int getMonotonicFunctionChildIndex() {
        return 0;
    }

    @Override
    public Expression withConstantArgs(Expression literal) {
        return new UnixTimestamp(literal);
    }

    @Override
    public boolean isMonotonic(Literal lower, Literal upper) {
        if (arity() != 1) {
            return false;
        }
        if (null == lower) {
            lower = DateTimeLiteral.MIN_DATETIME;
        }
        if (null == upper) {
            upper = DateTimeLiteral.MAX_DATETIME;
        }
        return true;
    }
}
